MINSALT. AN EXPERIMENT WITH UNSALTED ROADS AND STREETS ON GOTLAND

This study forms a subsidiary project in the major research project Reducing the damage from salt for road maintenance purposes - MINSALT carried on by the National Road Administration, The Swedish Association of Local Autohorities and the VTI for several winters. The Swedish National Testing Institute and the Swedish Corrosion Institute have been engaged in studies on Gotland. The purpose of the experiment on Gotland is to study the conse-quences for road users and road maintenance auhorities, as well as road user opinion, when salt is not used. Since the winter of 1986/87 no salt has been used in winter maintenance on Gotland. Studies have been made during the winter before the test and during the three first unsalted winters. The following effects were studied: road condition, traffic data, spot speed, accidents, corrosion, environmental impact, implemented actions and the cost of the road maintenance authority, road user opinion and experience of the road maintenance authority. Followup studies show for example that the experiment has had the following effects; an increase with two to three times of the number of days with icy and snow-covered roads, the change in the number of accidents differed in the three statistics sources used, corrosion damage to police cars was halved during the winter period, the areas affected by salt had a quick recovery when salting was discontinued and almost all road users are negative to the use of salt. (A)